A sol–gel synthesis to prepare size and shape-controlled mesoporous nanostructures of binary (II–VI) metal oxides. Issue 24 (6th April 2020)

• Record Type: Journal Article
• Authors: Yarbrough, Ryan; Davis, Klinton; Dawood, Sheeba; Rathnayake, Hemali
• Is Part Of: RSC advances. Volume 10:Issue 24(2020)
• Page Start: 14134
• Page End: 14146
• Publication Date: 2020-04-06
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d0ra01778g
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A base-catalyzed sol–gel approach combined with a solvent-driven self-assembly process at low temperature is augmented to make highly mesoporous metal oxide nanostructures of manganese and copper, and hydroxide nanostructures of magnesium. Abstract : A base-catalyzed sol–gel approach combined with a solvent-driven self-assembly process at low temperature is augmented to make manganese oxide (Mn3 O4 ), copper oxide (CuO), and magnesium hydroxide (Mg(OH)2 ) nanostructures with size- and shape-controlled morphologies. Nanostructures of Mn3 O4 with either hexagonal, irregular particle, or ribbon shape morphologies with an average diameter ranged from 100 to 200 nm have been prepared in four different solvent types. In all morphologies of Mn3 O4, the experimental XRD patterns have indexed the nanocrystal unit cell structure to triclinic. The hexagonal nanoparticles of Mn3 O4 exhibit high mesoporocity with a BET surface area of 91.68 m 2 g −1 and BJH desorption average pore diameter of ∼28 nm. In the preparation of CuO nanostructures, highly nanoporous thin sheets have been produced in water and water/toluene solvent systems. The simulated XRD pattern matches the experimental XRD patterns of CuO nanostructures and indexes the nanocrystal unit cell structure to monoclinic. With the smallest desorption total pore volume of 0.09 cm 3 g −1, CuO nanosheets have yielded the lowest BET surface area of 18.31 m 2 g −1 and a BHJ desorption average pore diameter of ∼16 nm. The sol of magnesium hydroxide nanocrystals produces highly nanoporous hexagonal nanoplates in water and water/toluene solvent systems. The wide angle powder XRD patterns show well-defined Bragg's peaks, indexing to a hexagonal unit cell structure. The hexagonal plates show a significantly high BET surface area (72.31 m 2 g −1 ), which is slightly lower than the surface area of Mn3 O4 hexagonal nanoparticles. The non-template driven sol–gel synthesis process demonstrated herein provides a facile method to prepare highly mesoporous and nanoporous nanostructures of binary (II–IV) metal oxides and their hydroxide derivatives, enabling potential nanostructure platforms with high activities and selectivities for catalysis applications.